Micro-battery, and PCB and semiconductor chip using same

ABSTRACT

A solid silicon secondary battery, by substitutions of silicon for lithium, enables decreasing of preparations cost and minimizing of environmental pollutions. By laminate pressing multiple times a positive or negative electrode material, the present invention enables increasing of the density of a positive or negative electrode active material, thereby increasing current density and capacity. By having mesh plates equipped inside the positive electrode active material and the negative electrode active material, the present invention enables effective moving of electrons. By enabling common use of an electrode, of a silicon secondary battery, connected during a serial connections of the silicon secondary battery, the present invention enables decreasing of the thickness of a silicon secondary battery assembly and increasing of output voltage. By being integrally formed with a PCB or a chip and supplying a power source, the present invention plays the role of a backup power source for instant discharging.

CROSS REFERENCE TO RELATED APPLICATIONS AND CLAIM OF PRIORITY

This application claims benefit under 35 U.S.C. 119(e), 120, 121, or365(c), and is a National Stage entry from International Application No.PCT/KR2015/007587, filed Jul. 21, 2015, which claims priority to thebenefit of Korean Patent Application No. 10-2014-0092518 filed in theKorean Intellectual Property Office on Jul. 22, 2014, the entirecontents of which are incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a micro-battery unit and a PCBsubstrate and semiconductor chip using the same.

BACKGROUND ART

As a secondary battery is a battery which converts chemical energy intoelectrical energy to supply power to an external circuit and, when thebattery is discharged, receives external power and converts electricalenergy into chemical energy so that electricity is stored therein, thesecondary battery is generally referred to as a storage battery.

Such secondary batteries include lead storage batteries, nickel-cadmiumsecondary batteries, lithium secondary batteries, and so on. A leadstorage battery is used for a vehicle because the lead storage batteryhas a high voltage but is bulky and heavy, a nickel-cadmium secondarybattery is used as a substitute for a dry cell, and a lithium secondarybattery is used for a power source of cameras, mobile phones, and so onbecause the lithium secondary battery is very light. The lithiumsecondary batteries among the above described secondary batteries havebeen widely used due to popularization of personal portable terminalssuch as smart phones and tablet personal computers (tablet PCs), whichhave been rapidly increasing recently.

However, in a lithium secondary battery, lithium as a main material isconsiderably expensive, and when a lithium secondary battery of whichlifetime is over is discarded, there is a problem in that lithium isdischarged from a waste disposal place and environmental pollution isinvolved.

Therefore, there is an urgent need to develop a high-power secondarybattery that can replace a lithium secondary battery.

SUMMARY

A first object of the present invention is to provide a high outputpower and high efficiency silicon secondary battery capable of replacinga lithium secondary battery.

A second object of the present invention is to provide a siliconsecondary battery capable of increasing the current density and capacitythereof by increasing the density of a positive or negative electrodeactive material by manufacturing the positive or negative electrodeactive material by stacking and pressing positive or negative electrodematerials several times.

A third object of the present invention is to provide a siliconsecondary battery capable of efficiently moving electrons by including amesh plate in a positive electrode active material and a negativeelectrode active material.

A fourth object of the present invention is to provide a siliconsecondary battery assembly capable of reducing a thickness of thesilicon secondary battery assembly and increasing an output voltagethereof by sharing an electrode of a silicon secondary battery which isused for a serial connection of the silicon secondary battery.

A fifth object of the present invention is to provide a siliconsecondary battery capable of serving as a backup power source againstinstantaneous discharging by being formed integrally with a printedcircuit board (PCB) or chip and supplying power.

One aspect of the present invention provides a micro-battery including asilicon secondary battery, wherein the silicon secondary batteryincludes: a first silicon multilayer thin film part in which a pluralityof silicon positive electrode thin film layers each formed of a firstsilicon compound, which generates silicon cations when the siliconsecondary battery is charged and generates silicon anions when thesilicon secondary battery is discharged, are stacked; a second siliconmultilayer thin film part in which a plurality of silicon negativeelectrode thin film layers each formed of a second silicon compound,which generates silicon anions when the silicon secondary battery ischarged and generates silicon cations when the silicon secondary batteryis discharged, are stacked; and a solid electrolyte layer locatedbetween the first silicon multilayer thin film part and the secondsilicon multilayer thin film part and configured to deliver silicon ionsbetween the first silicon multilayer thin film part and the secondsilicon multilayer thin film part when the silicon secondary battery ischarged and discharged.

A positive electrode collector may be bonded to one side surface of thefirst silicon multilayer thin film part, and a negative electrodecollector may be bonded to one side surface of the second siliconmultilayer thin film part.

One side end of the positive electrode collector may be bonded to asubstrate.

At least a part of portions of the negative electrode collector exceptfor a surface of the negative electrode collector in contact with thesecond silicon multilayer thin film part may be bonded to a substrate.

A space may be formed between the positive electrode collector and atleast side portions of the second silicon multilayer thin film part, thesolid electrolyte layer, and the negative electrode collector so thatthe second silicon multilayer thin film part, the solid electrolytelayer, and the negative electrode collector are insulated from thepositive electrode collector.

The space may be filled with an insulating material.

The first silicon compound and/or the second silicon compound mayinclude elastic carbon.

The first silicon compound and/or the second silicon compound mayfurther include conductive carbon.

The elastic carbon may include fullerene or expanded graphite.

The first silicon compound and/or the second silicon compound mayinclude inactive material particles.

The first silicon compound and/or the second silicon compound mayfurther include conductive carbon or a conductive polymer.

The positive electrode thin film layer and/or the negative electrodethin film layer may be formed in a mesh shape.

The first silicon multilayer thin film part and/or the second siliconmultilayer thin film part may include an interlayer formed of a metal orcarbon allotrope.

The interlayer may be thinner than the first silicon multilayer thinfilm part and the second silicon multilayer thin film part.

The metal may include any one selected among aluminum, gold, and silveror an alloy containing two or more of aluminum, gold, and silver.

The carbon allotrope may include any one selected among graphene, acarbon nanotube, and fullerene.

Concave-convex shapes may be formed on one surface or both surfaces ofthe positive electrode thin film layer and/or the negative electrodethin film layer.

A printed circuit board (PCB) substrate having a portion on which themicro-battery is mounted as a backup power source.

A semiconductor chip having a portion integrated with the micro-batteryserving as a backup power source using a deposition method.

Therefore, the present invention has the following effects.

First, by replacing lithium of a secondary battery with silicon, it ispossible to reduce manufacturing costs and minimize environmentalpollutions when the secondary battery is discarded.

Second, the current density and capacity of a silicon secondary batterycan be increased by increasing the density of a positive or negativeelectrode active material by manufacturing the positive or negativeelectrode active material by stacking and pressing positive or negativeelectrode materials several times.

Third, by including a mesh plate in a positive electrode active materialand a negative electrode active material, electrons can be efficientlymoved.

Fourth, since an electrode of a silicon secondary battery used for aserial connection of the silicon secondary battery is shared, athickness of a silicon secondary battery assembly can be reduced and anoutput voltage thereof can be increased.

Fifth, a silicon secondary battery can serve as a backup power sourceagainst instantaneous discharging by being formed integrally with aprinted circuit board (PCB) or chip and supplying power.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a view illustrating a structure of a silicon secondary batteryaccording to the present invention.

FIG. 2 is a view illustrating a structure of a silicon secondary batteryaccording to a first embodiment of the present invention.

FIG. 3 is a view illustrating a structure of a silicon secondary batteryaccording to a second embodiment of the present invention.

FIG. 4 is a view illustrating an example of a mesh plate included in anactive material of a silicon secondary battery according to a thirdembodiment of the present invention.

FIG. 5 is a view illustrating a structure of a silicon secondary batteryunit according to a fourth embodiment of the present invention.

FIG. 6 is a view illustrating an example of a battery module for anelectric vehicle to which the silicon secondary battery unit accordingto the fourth embodiment of the present invention is applied.

FIG. 7 is a view illustrating an example of a micro-battery according toa sixth embodiment of the present invention.

DETAILED DESCRIPTION

The terms and words used in the present specification and claims shouldnot be construed as limited to ordinary or dictionary meaning, andshould be interpreted as a meaning and concept corresponding to thetechnical concept of the present invention based on the principle thatthe concept of the term may be appropriately defined by the inventor inorder to explain the invention of the inventor in the best way.

Therefore, the embodiments described in the present specification andthe configurations shown in the drawings are only the most preferredembodiments of the present invention and are not intended to representall of the technical concepts of the present invention. Further, itshould be understood that various equivalents and modifications may bepresent at the time of filing the application. In the followingdescription, well-known functions or constructions are not described indetail when they are determined to obscure the gist of the presentinvention.

Hereinafter, a silicon secondary battery according to an exemplaryembodiment of the present invention and a method of manufacturing thesame will be described with reference to the accompanying drawings.

As the silicon secondary battery according to the present inventionrelates to a secondary battery charged and discharged using siliconions, as shown in FIG. 1, the silicon secondary battery includes apositive electrode active material layer 20 which generates siliconcations when the silicon secondary battery is charged and generatessilicon anions when the silicon secondary battery is discharged, anegative electrode active material layer 40 which generates siliconanions when the silicon secondary battery is charged and generatessilicon cations when the silicon secondary battery is discharged, and asolid electrolyte layer 10 located between the positive electrode activematerial layer 20 and the negative electrode active material layer 40and configured to deliver silicon ions between the positive electrodeactive material layer 20 and the negative electrode active materiallayer 40 when the silicon secondary battery is charged and discharged.

Further, referring to FIG. 1, a positive electrode collector 30 isbonded to the positive electrode active material layer 20, and anegative electrode collector 50 is bonded to the negative electrodeactive material layer 40.

Referring to FIG. 1, the positive electrode collector 30 is providedwith a metal plate having a predetermined thickness, and one sidethereof is coated with the positive electrode active material layer 20.The positive electrode active material layer 20 may be provided withsilicon carbide (SiC) but is not limited thereto. For example, thepositive electrode active material layer 20 may include silicon carbide(SiC) to which a small amount of germanium (Ge) is added. This may bemade by doping, and a positive electrode active material may be used byadding an element located in the same group as a group including carbon(C) in a periodic table of the elements.

The negative electrode collector 50 is provided with a metal platehaving a predetermined thickness of which one side is coated with thenegative electrode active material layer 40. The negative electrodeactive material layer 40 may be formed of silicon nitrate (Si₃N₄) but isnot limited thereto. For the negative electrode active material layer40, silicon nitrate (Si₃N₄), to which a small amount of an elementlocated in the same group as a group including nitrogen (N) of aperiodic table of the elements is added, may be also used as a negativeelectrode active material.

To describe the above doping again, an electrode serves to generate avoltage by a potential difference caused by the deviation of electronsgenerated in an ionization process. Silicon has bipolarity as an elementhaving an ionization degree of +4. In this bipolarity, a siliconelectrode doped with N and C is used for ease of electron deviation andease of acceptance. However, silicon carbide and silicon nitrate are ahexagonal crystalline material, electron transfer in a crystalline phaseis easy to occur on crystalline surfaces thereof, and in particular, anelectron deviation phenomenon may be changed according to crystallineorientation thereof. By adding a transition metal, such as Al, Fe, Mg,Zn, or Mn, to a raw material of silicon carbide and silicon nitrate, thecrystalline orientation is changed so that deviation and acceptance ofelectrons may be easily controlled. Electron mobility may be controlledby adding a four or five periodic transition metal, which has a greaterion diameter than that of silicon, so as to provide orientation tocrystals. When elements such as Al, P, S, Mg, and Na, which are threeperiodic elements having a similar diameter to that of silicon, areadded in combination, the change in a shape of a crystalline phase canbe minimized and the degree of electron deviation can be controlled.

Meanwhile, the solid electrolyte layer 10 is a nonaqueous electrolytewhich is in a fixed state and may be provided with an ion exchange resinmade of a polymer, an ion exchange inorganic compound made of a metaloxide, or the like. For the ion exchange resin, any one of polymershaving any type among a cationic sulfonic acid group (—SO₃H), a carboxylgroup (—COOH), an anionic quaternary ammonium group (—N(CH₃)²C₂H₄OH), asubstituted amino group (—NH(CH₃), and the like as a binder may beemployed. Among the above polymers, polyacrylamide methyl propanesulfonic acid (PAMPS) having the sulfonic acid group (—SO₃H) may besuitably employed in terms of smoothly moving electrons (e⁻).

The solid electrolyte layer 10 described above enhances the usability ofa battery by adding a polymer to an electrolyte for providing a fixingproperty of a gel-like shape. However, since a polymer is composed of achain composed of a single bond or a chain composed of a double bond,electron density is very low when only electrons are shared in the chainand electron mobility is lower than when a liquid electrolyte is usedalone. Such a polymer has to transport large quantities of electrons andions in a short period of time and further improve the fixability of aliquid electrolyte to improve safety and stability. A polymer for liquidphase fixation requires a high molecular weight material for highviscosity but tends to lower the conductivity of the polymer withincreasing molecular weight, and thus two or more types of polymers witha low molecular weight and a low polymerization degree for highconductivity and a polymer with a high polymerization degree for highviscosity may be mixed to compensate for ion mobility and electronmobility.

As described above, the positive electrode collector 30 and the negativeelectrode collector 50 coated with the positive electrode activematerial layer 20 and the negative electrode active material layer 40are combined with the solid electrolyte layer 10 to form a siliconsecondary battery. At this time, the positive electrode active materiallayer 20 and the negative electrode active material layer 40 are bondedto be in contact with both surfaces of the solid electrolyte layer 10.

The silicon secondary battery constructed as described above is chargedand discharged by movement of electrons to serve as a battery.

In the above-described silicon secondary battery, electrons move towardthe negative electrode collector 50 when a current is applied to thepositive electrode collector 30. As a first step, the transferredelectrons make excess electrons to be stored when compared with avoltage equilibrium state due to an electric field generated by formingdipole in the solid electrolyte layer 10, and charging speed is veryfast. Electrons charged by electromagnetic force move to an interface ofa negative electrode active material layer 40 side of the solidelectrolyte layer 10, fill silicon holes existing on a surface of thenegative electrode active material layer 40, and are sequentially moved.In this process, silicon carbide molecules existing in the negativeelectrode active material layer 40 are physically bonded. When thenegative electrode active material layer 40 is saturated with electronsby processing the physical bonding for a predetermined period of time,the electrons maintain the physical bonding, and ultimately theelectrons transferred by the current applied to the positive electrodecollector 30 are chemically bonded with silicon carbide contained in thenegative electrode active material layer 40, thereby completing achemical charge inside the battery. Therefore, the silicon secondarybattery simultaneously has physical fast charge characteristics andchemical stable charge characteristics.

In the present invention, the positive electrode active material layer20 and/or the negative electrode active material layer 40 may includeelastic carbon to prevent the degradation of the charge and dischargecharacteristics of the active material layer because the volume of theactive material layer is increased as the silicon secondary battery isrepeatedly charged and discharged. Since the positive electrode activematerial layer 20 and/or the negative electrode active material layer 40include elastic carbon, even when silicon particles are enlarged due torepeated charge and discharge, a volume offset effect may be shown bythe elastic carbon, thereby suppressing the bulking of the entire activematerial layer.

However, when the positive electrode active material layer 20 and/or thenegative electrode active material layer 40 include elastic carbon,since ion mobility or electron conductivity may be slightly lowered dueto a gap between silicon particles and elastic carbon, in order tocompensate for this, it may be preferable to further include conductivecarbon or to use fullerene simultaneously having elasticity and high ionmobility or electron conductivity as the elastic carbon.

As another example, in the present invention, the positive electrodeactive material layer 20 and/or the negative electrode active materiallayer 40 may include inactive material particles, which do notparticipate in a bulking reaction of the active material layer, toprevent the degradation of the charge and discharge characteristicscaused when the volume of the active material layer is increased as thesilicon secondary battery is repeatedly charged and discharged. Theinactive material particles are one or more metal particles selectedfrom the group consisting of Mo, Cu, Fe, Co, Ca, Cr, Mg, Mn, Nb, Ni, Ta,Ti, and V.

However, when the positive electrode active material layer 20 and/or thenegative electrode active material layer 40 include the inactivematerial particles as described above, since an electric capacity of thesilicon secondary battery may be slightly reduced, it may be preferableto further include conductive carbon or conductive polymer.

In the present invention, the positive electrode active material layer20 and/or the negative electrode active material layer 40 may have anyshape which may form a layer, but it may be preferable to have a meshshape to minimize the risk of breakage of the active material layer dueto contraction and expansion of the active material layer caused byrepeatedly charging and discharging the silicon secondary battery.

In the present invention, the positive electrode active material layer20 and/or the negative electrode active material layer 40 are notparticularly limited in a surface shape, but it is preferable that aninterface contact area with the solid electrolyte layer 10 and/or thepositive and negative electrode collectors 30 and 50 be widen andconcavo-convex shapes be formed on one or both surfaces of the activematerial layer to reduce interfacial resistance.

In the solid electrolyte layer 10 of the present invention, in order toincrease battery capacity by reducing interfacial resistance between thesolid electrolyte layer and the positive electrode active materiallayer, it may be preferable that a first interlayer (not shown)including a positive electrode active material layer component and asolid electrolyte component be formed between the solid electrolytelayer and the positive electrode active material layer.

A content ratio of components of the first interlayer is notparticularly limited, but it is preferable that the content of thepositive electrode active material layer component be larger than thatof the solid electrolyte component to further increase the electriccapacity of the silicon secondary battery, and a thickness of the firstinterlayer is not particularly limited either, but it is preferable thatthe thickness be smaller than a thickness of the solid electrolyte layerand/or the positive electrode active material layer to further increasethe electric capacity of the silicon secondary battery.

Further, it is preferable that the first interlayer have protrusionsformed on one or both surfaces thereof to further reduce interfaceresistance with an adjacent layer.

As another example, in the solid electrolyte layer 10 of the presentinvention, in order to increase battery capacity by reducing interfacialresistance between the solid electrolyte layer and the negativeelectrode active material layer, it may be preferable that a secondinterlayer (not shown) including a negative electrode active materiallayer component and a solid electrolyte component be formed between thesolid electrolyte layer and the negative electrode active materiallayer.

A content ratio of components of the second interlayer is notparticularly limited, but it is preferable that the content of thenegative electrode active material layer component be larger than thatof the solid electrolyte component to further increase the electriccapacity of the silicon secondary battery, and a thickness of the secondinterlayer is not particularly limited either, but it is preferable thatthe thickness be smaller than a thickness of the solid electrolyte layerand/or the negative electrode active material layer to further increasethe electric capacity of the silicon secondary battery.

Further, it is preferable that the second interlayer have protrusionsformed on one or both surfaces thereof to further reduce interfaceresistance with an adjacent layer.

Meanwhile, the solid electrolyte layer 10 may preferably include one ormore among polyvinylidene fluoride (PVDF) and polytetrafluoroethylene(PTFE) in order to further increase mechanical strength and improveprocessability, and in this case, it may be more preferable to furtherinclude conductive polymer because electron conductivity thereof may bereduced slightly.

In the present invention, the positive electrode collector 30 and thenegative electrode collector 50 are respectively bonded to the positiveelectrode active material layer and the negative electrode activematerial layer and collect charges, and stainless steel, nickel, or thelike may be used as materials of the positive electrode collector 30 andthe negative electrode collector 50.

The positive electrode collector and/or the negative electrode collectorare not particularly limited in shape, but it may be preferable to havea porous net shape or a foamed shape to reduce interfacial resistance byincreasing an interface contact area between the collector and theactive material layer. The porous net shape may be a two-dimensionalplanar porous net shape or a three-dimensional porous net shape.

Further, when the positive electrode collector and/or the negativeelectrode collector are formed in a porous or foamed shape, any one ofgold, silver and a conductive polymer may be coated on a surface of thepositive electrode collector and/or the negative electrode collector,thereby further increasing the electron and ion conductivity of thecollector and further reducing the interfacial resistance. Inparticular, when the surface is coated with the conductive polymer,interfacial adhesion may be further enhanced because the conductivepolymer acts as a conductive agent and also acts as a binder. Theconductive polymer may be any type of polymer having conductivity, butit is preferable to use any one selected from the group consisting ofpolypyrrole, polyaniline, polythiophene, and polyacetylene in view ofimproving conductivity and interfacial adhesion of the collector.

<First Embodiment>

Hereinafter, a silicon secondary battery according to a first embodimentof the present invention will be described in detail with reference toFIG. 2.

The silicon secondary battery according to the first embodiment of thepresent invention includes a first silicon multilayer thin film part 200in which a plurality of silicon positive electrode thin film layers 210formed of a first silicon compound, which generates silicon positiveions when the silicon secondary battery is charged and generates siliconnegative ions when the silicon secondary battery is discharged, arestacked, a collector 300 bonded to the first silicon multilayer thinfilm part 200, and a second silicon multilayer thin film part 400 inwhich a plurality of silicon negative electrode thin film layers eachformed of a second silicon compound, which generates silicon negativeions when the silicon secondary battery is charged and generates siliconpositive ions when the silicon secondary battery is discharged, arestacked, a collector 500 bonded to the second silicon multilayer thinfilm part 400, and a solid electrolyte layer 100 located between thefirst silicon multilayer thin film part 200 and the second siliconmultilayer thin film part 400 and configured to deliver silicon ionsbetween the first silicon multilayer thin film part 200 and the secondsilicon multilayer thin film part 400 when the silicon secondary batteryis charged and discharged.

The first silicon multilayer thin film part 200 is formed by stackingand pressing a plurality of silicon positive electrode thin film layers210. The silicon positive electrode thin film layer 210 is formed bypressing a first silicon compound mixed with a bonding material.Alternatively, the silicon positive electrode thin film layer 210 may beformed by pressing a first silicon compound coated with a bondingmaterial. The plurality of silicon positive electrode thin film layers210 each formed as described above are stacked and pressurized to formthe first silicon multilayer thin film part 200. Here, the first siliconcompound may be provided with silicon carbide, and the bonding materialmay be provided with a polymeric crosslinking agent.

The first silicon multilayer thin film part 200 formed as describedabove is bonded to the collector 300 so that a positive electrodecollector is formed. Here, the collector 300 may be formed of a metalmaterial in a porous net shape, and a terminal for supplying a currentmay be formed on an end portion thereof. Here, the first siliconmultilayer thin film part 200 may be bonded to the collector 300 using aseparate bonding material or bonding member, or using a simpleattachment, printing, or pressing manner.

Meanwhile, the second silicon multilayer thin film part 400 is formed bystacking and pressing a plurality of silicon negative electrode thinfilm layers 410. The silicon negative electrode thin film layer 410 isformed by pressing a second silicon compound mixed with a bondingmaterial. Alternatively, the silicon negative electrode thin film layer410 may be formed by pressing a second silicon compound coated with abonding material. The plurality of silicon negative electrode thin filmlayers 410 each formed as described above are stacked and pressurized toform the second silicon multilayer thin film part 400. Here, the secondsilicon compound may be provided with silicon nitrate, and the bondingmaterial may be provided with a polymeric crosslinking agent.

The second silicon multilayer thin film part 400 formed as describedabove is bonded to the collector 500 so that a negative electrodecollector is formed. Here, the collector 500 may be formed of a metalmaterial in a porous net shape, and a terminal for supplying a currentmay be formed on an end portion thereof. Here, the second siliconmultilayer thin film part 400 may be bonded to the collector 500 using aseparate bonding material or bonding member, or using a simpleattachment, printing, or pressing manner.

The positive electrode and negative electrode collectors formed asdescribed above are bonded to the solid electrolyte layer 100 so thatthe first and second silicon multilayer thin film parts 200 and 400 arein contact with an outer surface of the solid electrolyte layer 100.Here, the first and second silicon multilayer thin film parts 200 and400 may be bonded to the solid electrolyte layer 100 using a separatebonding material or bonding member, or using a simple attachment,printing, spraying, or pressing manner. Here, the solid electrolytelayer 100 is formed to have a greater width than the first and secondsilicon multilayer thin film parts 200 and 400 to prevent a shortcircuit between a positive electrode and negative electrode.

In the above described silicon secondary battery according to the firstembodiment of the present invention, the first or second siliconmultilayer thin film part 200 or 400 is manufactured by stacking andpressing the first silicon compound or second silicon compound multipletimes, and thus the density of the first or second silicon multilayerthin film part 200 or 400 is increased and the current density andcapacity of the silicon secondary battery can be increased.

In the solid electrolyte layer 100 of the first embodiment of thepresent invention, it is preferable to form a first interlayer includinga first silicon compound and a solid electrolyte component between thesolid electrolyte layer and the first silicon multilayer thin film partin order to increase battery capacity by decreasing interfacialresistance between the solid electrolyte layer and the first siliconmultilayer thin film part.

A content ratio of components of the first interlayer is notparticularly limited, but it is preferable that the content of the firstsilicon compound be larger than that of the solid electrolyte componentto further increase the electric capacity of the silicon secondarybattery, and a thickness of the first interlayer is not particularlylimited either, but it is preferable that the thickness be smaller thana thickness of the solid electrolyte layer and/or the first siliconmultilayer thin film part to further increase the electric capacity ofthe silicon secondary battery.

Further, it is preferable that the first interlayer have protrusionsformed on one or both surfaces thereof to further reduce interfaceresistance with an adjacent layer.

As another example, in the solid electrolyte layer 100 of the firstembodiment of the present invention, it is preferable to form a secondinterlayer including a second silicon compound and a solid electrolytecomponent between the solid electrolyte layer and the second siliconmultilayer thin film part in order to increase battery capacity bydecreasing interfacial resistance between the solid electrolyte layerand the second silicon multilayer thin film part.

A content ratio of components of the second interlayer is notparticularly limited, but it is preferable that the content of thesecond silicon compound be larger than that of the solid electrolytecomponent to further increase the electric capacity of the siliconsecondary battery, and a thickness of the second interlayer is notparticularly limited either, but it is preferable that the thickness besmaller than a thickness of the solid electrolyte layer and/or thesecond silicon multilayer thin film part to further increase theelectric capacity of the silicon secondary battery.

Further, it is preferable that the second interlayer have protrusionsformed on one or both surfaces thereof to further reduce interfaceresistance with an adjacent layer.

Meanwhile, the solid electrolyte layer 100 may preferably include one ormore among PVDF and PTFE in order to further increase mechanicalstrength and improve processability, and in this case, it may be morepreferable to further include a conductive polymer because electronconductivity thereof may be reduced slightly.

<Second Embodiment>

Hereinafter, a silicon secondary battery according to a secondembodiment of the present invention will be described in detail withreference to FIG. 3.

The silicon secondary battery according to the second embodiment of thepresent invention includes a first silicon multilayer thin film part 200in which a plurality of silicon positive electrode thin film layers 210formed of a first silicon compound, which generates silicon cations whenthe silicon secondary battery is charged and generates silicon anionswhen the silicon secondary battery is discharged, are stacked, acollector 300 bonded to the first silicon multilayer thin film part 200,a second silicon multilayer thin film part 400 in which a plurality ofsilicon negative electrode thin film layers 410 formed of a secondsilicon compound, which generates silicon anions when the siliconsecondary battery is charged and generates silicon cations when thesilicon secondary battery is discharged, are stacked, a collector 500bonded to the second silicon multilayer thin film part 400, a separationlayer 600 located between the first silicon multilayer thin film part200 and the second silicon multilayer thin film part 400, a liquidelectrolyte 100′ for delivering silicon ions between the first siliconmultilayer thin film part 200 and the second silicon multilayer thinfilm part 400 when the silicon secondary battery is charged anddischarged.

The first silicon multilayer thin film part 200 is formed by stackingand pressing a plurality of silicon positive electrode thin film layer210. The silicon positive electrode thin film layer 210 is formed bypressing a first silicon compound mixed with a bonding material.Alternatively, the silicon positive electrode thin film layer 210 may beformed by pressing a first silicon compound coated with a bondingmaterial. The plurality of silicon positive electrode thin film layers210 each formed as described above is stacked and pressurized to formthe first silicon multilayer thin film part 200. Here, the first siliconcompound may be provided with silicon carbide, and the bonding materialmay be provided with a polymeric crosslinking agent.

The first silicon multilayer thin film part 200 formed as describedabove is bonded to the collector 300 so that a positive electrodecollector is formed. Here, the collector 300 may be formed of a metalmaterial in a porous net shape, and a terminal for supplying a currentmay be formed on an end portion thereof. Here, the first siliconmultilayer thin film part 200 may be bonded to the collector 300 using aseparate bonding material or bonding member, or using a simpleattachment, printing, or pressing manner.

Meanwhile, the second silicon multilayer thin film part 400 is formed bystacking and pressing a plurality of silicon negative electrode thinfilm layers 410. The silicon negative electrode thin film layer 410 isformed by pressing a second silicon compound mixed with a bondingmaterial. Alternatively, the silicon negative electrode thin film layer410 may be formed by pressing a second silicon compound coated with abonding material. The plurality of silicon negative electrode thin filmlayers 410 each formed as described above are stacked and pressurized toform the second silicon multilayer thin film part 400. Here, the secondsilicon compound may be provided with silicon nitrate, and the bondingmaterial may be provided with a polymeric crosslinking agent.

The second silicon multilayer thin film part 400 formed as describedabove is bonded to the collector 500 so that a negative electrodecollector is formed. Here, the collector 500 may be formed of a metalmaterial in a porous net shape, and a terminal for supplying a currentmay be formed on an end portion thereof. Here, the second siliconmultilayer thin film part 400 may be bonded to the collector 500 using aseparate bonding material or bonding member, or using a simpleattachment, printing, or pressing manner.

In the positive electrode and negative electrode collectors formed asdescribed above, the separation layer 600 is interposed between thefirst and second silicon multilayer thin film parts 200 and 400 toprevent a short circuit between a positive electrode and a negativeelectrode. Further, the first and second silicon multilayer thin filmparts 200 and 400 are bonded to the separation layer 600 to be formed inan impregnated form in the liquid electrolyte 100′.

In the above described silicon secondary battery according to the secondembodiment of the present invention, the first or second siliconmultilayer thin film part 200 or 400 is manufactured by stacking andpressing the first silicon compound or second silicon compound multipletimes, and thus the density of the first or second silicon multilayerthin film part 200 or 400 is increased and the current density andcapacity of the silicon secondary battery can be increased.

In the first and second embodiments of the present invention, the firstsilicon compound and/or the second silicon compound may include elasticcarbon to prevent the degradation of the charge and dischargecharacteristics of an active material layer because the volume of theactive material layer is increased as the silicon secondary battery isrepeatedly charged and discharged. Since the first silicon compoundand/or the second silicon compound include elastic carbon, even whensilicon particles are enlarged due to repeated charge and discharge, avolume offset effect may be shown by the elastic carbon, therebysuppressing the bulking of the entire active material layer.

However, when the first silicon compound and/or the second siliconcompound include elastic carbon, since ion mobility or electronconductivity may be slightly lowered due to a gap between siliconparticles and elastic carbon, in order to compensate for this, it may bepreferable to further include conductive carbon or to use fullerenesimultaneously having elasticity and high ion mobility or electronconductivity as the elastic carbon.

Further, in the first and second embodiments of the present invention,the first silicon compound and/or the second silicon compound mayinclude inactive material particles, which do not participate in abulking reaction of the active material layer, to prevent thedegradation of the charge and discharge characteristics caused when thevolume of the active material layer is increased as the siliconsecondary battery is repeatedly charged and discharged. The inactivematerial particles are one or more metal particles selected from thegroup consisting of Mo, Cu, Fe, Co, Ca, Cr, Mg, Mn, Nb, Ni, Ta, Ti, andV.

However, when the first silicon compound and/or the second siliconcompound include the inactive material particles as described above,since the electric capacity of the silicon secondary battery may beslightly reduced, it may be preferable to further include conductivecarbon or conductive polymer.

In the first and second embodiments of the present invention, thepositive electrode thin film layer and/or the negative electrode thinfilm layer may have any shape which may form a layer, but it may bepreferable to have a mesh shape to minimize the risk of breakage of thethin film layer due to contraction and expansion of the positiveelectrode thin film layer and/or the negative electrode thin film layercaused by repeatedly charging and discharging the silicon secondarybattery.

In the first and second embodiments of the present invention, thepositive electrode thin film layer and/or the negative electrode thinfilm layer are not particularly limited in a surface shape, but it ispreferable that an interface contact area with an adjacent layer bewiden and concavo-convex shapes be formed on one or both surfaces of thethin film layer to reduce interfacial resistance.

In the first and second embodiments of the present invention, the firstsilicon multilayer thin film part and/or the second silicon multilayerthin film part may be preferable to include an interlayer formed of ametal or carbon allotrope to improve charge and dischargecharacteristics and to secure uniform ion conductivity.

A thickness of the interlayer is not particularly limited, but it may bepreferable that the thickness be smaller than those of the first siliconmultilayer thin film part and the second silicon multilayer thin filmpart in view of increasing an electric capacity thereof.

A metal included in the interlayer may be any metal having high electricconductivity, but it may be preferable to use one selected amongaluminum, gold, and silver or an alloy containing two or more ofaluminum, gold, and silver in view of maximizing the performance ofcharge and discharge of a battery.

Further, a type of carbon allotrope included in the interlayer is notparticularly limited, but it may be preferable to use one selected amonggraphene, a carbon nanotube, and fullerene in view of securing uniformion conductivity in an electrode.

Hereinafter, a method of manufacturing the silicon secondary batteryaccording to the first and second embodiments of the present inventionwill be described.

The method of manufacturing the silicon secondary battery according tothe first and second embodiments of the present invention includesmanufacturing a first silicon multilayer thin film part by repeatedlystacking a plurality of silicon positive electrode thin film layers eachformed of a first silicon compound, manufacturing a positive electrodecollector by bonding the first silicon multilayer thin film part to acollector, manufacturing a second silicon multilayer thin film part byrepeatedly stacking a plurality of silicon negative electrode thin filmlayers each formed of a second silicon compound, manufacturing anegative electrode collector by bonding the second silicon multilayerthin film part to a collector, and bonding the first and second siliconmultilayer thin film parts to an electrolyte part.

First, the manufacturing of the first silicon multilayer thin film partis started from mixing the first silicon compound and a bondingmaterial. Here, the first silicon compound may be provided with siliconcarbide, and the bonding material may be provided with a polymericcrosslinking agent.

When the first silicon compound and the bonding material are mixed asdescribed above, the silicon positive electrode thin film layer in athin film shape is manufactured by pressing the mixed material.

The plurality of silicon positive electrode thin film layersmanufactured as described above are stacked and pressurized tomanufacture the first silicon multilayer thin film part.

When the first silicon multilayer thin film part is manufactured by theabove described manner, moldability thereof is high but internalresistance of a battery may be increased because pores are generated inthe first silicon multilayer thin film part.

Further, the first silicon multilayer thin film part may be manufacturedas described below.

Each particle of the first silicon compound is coated with a bondingmaterial, and the coated first silicon compound is dried andmanufactured in a powder form.

Then, the first silicon compound dried and manufactured in a powder formis pressurized to manufacture the silicon positive electrode thin filmlayer in a thin film form, and the plurality of manufactured siliconpositive electrode thin film layers are stacked and pressurized tomanufacture the first silicon multilayer thin film part.

When the first silicon multilayer thin film part is manufactured by theabove described manner, moldability thereof is low but internalresistance of a battery may be decreased because pores are not generatedin the first silicon multilayer thin film part.

When the first silicon multilayer thin film part is manufactured asdescribed above, the first silicon multilayer thin film part is bondedto a collector to manufacture the positive electrode collector. Here,the first silicon multilayer thin film part may be bonded to thecollector using a separate bonding material or bonding member, or usinga simple attachment, printing, or pressing manner. Here, the collectoris formed of a metal material in a porous net shape, and a terminal forsupplying a current may be formed on an end portion thereof.

Further, the manufacturing of the second silicon multilayer thin filmpart is started from mixing the second silicon compound and a bondingmaterial. Here, the second silicon compound may be provided with siliconnitrate, and the bonding material may be provided with a polymericcrosslinking agent.

When the second silicon compound and the bonding material are mixed asdescribed above, the mixed material is pressurized to manufacture thesilicon negative electrode thin film layer in a thin film shape.

The plurality of silicon negative electrode thin film layersmanufactured as described above are stacked and pressurized tomanufacture the second silicon multilayer thin film part.

When the second silicon multilayer thin film part is manufactured by theabove described manner, moldability thereof is high but internalresistance of a battery may be increased because pores are generated inthe second silicon multilayer thin film part.

Further, the second silicon multilayer thin film part may bemanufactured as described below.

Each particle of the second silicon compound is coated with a bondingmaterial, and the coated second silicon compound is dried andmanufactured in a powder form.

Then, the second silicon compound dried and manufactured in a powderform is pressurized to manufacture the silicon negative electrode thinfilm layer in a thin film shape, and the plurality of manufacturedsilicon negative electrode thin film layers are stacked and pressurizedto manufacture the second silicon multilayer thin film part.

When the second silicon multilayer thin film part is manufactured by theabove described manner, moldability thereof is low but internalresistance of a battery may be decreased because pores are not generatedin the second silicon multilayer thin film part.

When the second silicon multilayer thin film part is manufactured asdescribed above, the second silicon multilayer thin film part is bondedto a collector to manufacture the negative electrode collector. Here,the second silicon multilayer thin film part may be bonded to thecollector using a separate bonding material or bonding member, or usinga simple attachment, printing, or pressing manner. Here, the collectormay be formed of a metal material in a porous net shape, and a terminalfor supplying a current may be formed on an end portion thereof.

When the positive electrode collector and the negative electrodecollector are manufactured as described above, the positive electrodecollector and the negative electrode collector are bonded to theelectrolyte part.

When the electrolyte part is in a solid state, the first and secondsilicon multilayer thin film parts of the positive electrode collectorand the negative electrode collector are bonded to be in contact with anouter surface of the solid electrolyte. Here, the first and secondsilicon multilayer thin film parts and the solid electrolyte may bebonded using a separate bonding material or bonding member, or using asimple attachment, printing, spaying, or pressing manner. Here, thesolid electrolyte is formed to have a greater width than those of thefirst and second silicon multilayer thin film parts to prevent a shortcircuit between a positive electrode and a negative electrode.

Further, when the electrolyte part is in a liquid state, a separationlayer is interposed between the first and second silicon multilayer thinfilm parts of the positive electrode collector and the negativeelectrode collector, and the first and second silicon multilayer thinfilm parts and the separation layer are bonded to be formed in animpregnated form in the liquid electrolyte.

In the silicon secondary battery manufactured by the above describedmanner, since the first silicon compound or second silicon compound isstacked and pressurized multiple times to manufacture the first orsecond silicon multilayer thin film part, the density of the first orsecond silicon multilayer thin film part is increased and the currentdensity and capacity of the silicon secondary battery can be increased.

<Third Embodiment>

Hereinafter, a silicon secondary battery according to a third embodimentof the present invention will be described.

The silicon secondary battery according to the third embodiment of thepresent invention includes a positive electrode coated with a positiveelectrode active material which generates silicon cations when thesilicon secondary battery is charged and generates silicon anions whenthe silicon secondary battery is discharged, a negative electrode coatedwith a negative electrode active material which generates silicon anionswhen the silicon secondary battery is charged and which generatessilicon cations when the silicon secondary battery is discharged, and asolid electrolyte layer located between the positive electrode andnegative electrode and configured to deliver silicon ions between thepositive electrode active material and the negative electrode activematerial when the silicon secondary battery is charged and discharged,wherein the present invention relates to the silicon secondary batteryincluding a mesh plate included in the positive electrode activematerial and/or the negative electrode active material.

First, the positive electrode is a metal plate having a predeterminedthickness, and a positive electrode active material is coated on oneside thereof. The positive electrode active material may be providedwith silicon carbide (SiC), but is not limited thereto.

The negative electrode is also provided with a metal plate having apredetermined thickness, and a negative electrode active material iscoated on one side thereof. The negative electrode active material maybe provided with silicon nitrate (Si₃N₄), but is not limited thereto.

The mesh plate is included in the positive electrode active material andthe negative electrode active material coated as described above. Asshown in FIG. 4, the mesh plate is formed in a net form, in which emptyspaces are formed, and inserted into the positive electrode activematerial and the negative electrode active material. Here, the meshplate is formed of a metal paste. The metal paste is a gel-type productmanufactured by mixing a powder of a metal and a liquid-state organicmaterial and is a metal material on which a metal pattern is easilyformed by a silk-screen or inkjet method. The metal paste may be easilymanufactured due to characteristics of having only a metal material byburning out or vaporizing a liquid-state organic material at lowtemperature, and when a pattern for printing is manufactured by asilk-screen method, a thickness of 30 μm or less may be manufactured sothat an increase in the thickness thereof is very small.

As described above, the positive electrode and the negative electrodewhich are respectively coated with the positive electrode activematerial and the negative electrode active material are bonded to thesolid electrolyte layer to form the silicon secondary battery. Here, thepositive electrode and the negative electrode are bonded to the solidelectrolyte layer so that the positive electrode active material and thenegative electrode active material are in contact with the solidelectrolyte layer.

The silicon secondary battery formed as described above is charged anddischarged by movement of electrons and serves as a battery.

Hereinafter, a method of manufacturing the silicon secondary batteryaccording to the third embodiment of the present invention will bedescribed in detail.

First, a base film is provided. The base film is formed of a syntheticresin material and has solubility.

Then, a positive electrode active material is coated on one surface ofthe base film.

As described above, when the positive electrode active material iscoated on the one surface of the base film, punching is performed on thepositive electrode active material to form a plurality of holes.

Then, a metal paste is coated on an upper portion of the positiveelectrode active material to form a mesh plate 700. Here, as shown inFIG. 4, the mesh plate 700 is formed in a net form and formed byprinting in a silk-screen manner. Here, the mesh plate 700 is disposedon upper portions of holes made by punching the positive electrodeactive material and the metal paste is introduced into the holes.

When the mesh plate is formed as described above, an upper portionthereof is coated with the positive electrode active material again.

Then, the positive electrode active material including the mesh platetherein is manufactured by a pressing method using heat and pressure.

When the positive electrode active material is manufactured as describedabove, the negative electrode active material is manufactured using thesame method as the above described method.

First, a base film is provided. The base film is formed of a syntheticresin material and has solubility.

Then, a negative electrode active material is coated on one surface ofthe base film.

As described above, when the negative electrode active material iscoated on the one surface of the base film, punching is performed on thenegative electrode active material to form a plurality of holes.

Then, a metal paste is coated on an upper portion of the negativeelectrode active material to form a mesh plate. Here, as shown in FIG.4, the mesh plate is formed in a net form and formed by printing in asilk-screen manner. Here, the mesh plate is disposed on upper portionsof holes made by punching the negative electrode active material and themetal paste is introduced into the holes.

When the mesh plate is formed as described above, an upper portionthereof is coated with the negative electrode active material again.

Then, the negative electrode active material including the mesh platetherein is manufactured by a pressing method using heat and pressure.

When the positive electrode active material and the negative electrodeactive material are manufactured as described above, the base films areremoved from the positive electrode active material and the negativeelectrode active material, and then the metal plates instead of the basefilms are mounted to manufacture the positive electrode and the negativeelectrode.

As described above, when the positive electrode and the negativeelectrode are manufactured, the positive electrode, the solidelectrolyte layer, and the negative electrode are sequentially stacked.Here, the positive electrode, the solid electrolyte layer, and thenegative electrode are stacked so that the positive electrode activematerial and the negative electrode active material are in contact withthe solid electrolyte layer.

Then, the silicon secondary battery is manufactured by a pressing methodusing heat and pressure.

In the silicon secondary battery using the solid electrolyte, the meshplate in a net form is included in an electrode using a metal paste,holes are made in connection portions of the mesh plate so that themetal paste is introduced into spaces in the holes, and thus higherelectron transfer speed can be provided when electrons generated betweenthe electrode and the electrolyte pass through the electrode.

Further, non-uniform reactivity between the electrode and theelectrolyte formed to be planar is changed to uniform reactivity by themesh plate in a net form, and thus conditions under which electrons areuniformly moved can be formed. Further, since movement of electrons isquickly performed through the holes made in the electrode, stacking iseasily achieved using a metal thin film or by coating when secondarybatteries are stacked.

<Fourth Embodiment>

Hereinafter, a silicon secondary battery unit according to a fourthembodiment of the present invention will be described in detail.

Referring to FIG. 5, in the silicon secondary battery unit according tothe fourth embodiment of the present invention, a plurality of siliconsecondary battery unit cells each including a positive electrode activematerial layer 1100 formed of a first silicon compound which generatessilicon cations when the silicon secondary battery is charged andgenerates silicon anions when the silicon secondary battery isdischarged, a negative electrode active material layer 1200 formed of asecond silicon compound which generates silicon anions when the siliconsecondary battery is charged and generates silicon cations when thesilicon secondary battery is discharged, and a solid electrolyte layer1000 are stacked to form a unit, the plurality of silicon secondarybattery unit cells are connected in series and stacked, and a commoncollector layer 1300 is interposed between the positive electrode activematerial layer 1100 and the negative electrode active material layer1200 so that charges are collected.

Since the first silicon compound and the second silicon compound aredescribed in detail above, repeated descriptions thereof will beomitted.

In the fourth embodiment of the present invention, the positiveelectrode active material layer 1100 may be either a single layerstructure or a multilayer structure, but it is preferable to have afirst silicon multilayer thin film part in which a plurality of siliconpositive electrode thin film layers, each of which is formed of a firstsilicon compound which generates silicon cations when the siliconsecondary battery is charged and generates silicon anions when thesilicon secondary battery is discharged, are stacked, in order tomaximize an electric capacity and charge and discharge characteristicsthereof based on a volume of the silicon secondary battery unit.

The negative electrode active material layer may also be either a singlelayer structure or a structure, but it is preferable to have a secondsilicon multilayer thin film part in which a plurality of siliconnegative electrode thin film layers, each of which is formed of a secondsilicon compound which generates silicon anions when the siliconsecondary battery is charged and generates silicon cations when thesilicon secondary battery is discharged, are stacked, in order tomaximize the electric capacity and charge and discharge characteristicsthereof based on the volume of the silicon secondary battery unit.

In the fourth embodiment of the present invention, the common collectorlayer 1300 performs both functions of a positive electrode collector anda negative electrode collector by being stacked between the positiveelectrode active material layer and the negative electrode activematerial layer included in the silicon secondary battery unit of thepresent invention, stainless steel, nickel, and so on may be used for amaterial thereof, a shape thereof is not particularly limited, and it ispreferable to have a porous net shape or foamed shape to reduceinterfacial resistance by increasing an interface contact area betweenthe common collector layer 1300 and the active material layers 1100 and1200 and to improve interfacial adhesion in a pressing process. Theporous net shape may be a two-dimensional planar porous net shape orthree-dimensional porous net shape.

Further, when the common collector layer 1300 has a porous net shape orfoamed shape, a surface of the common collector layer 1300 is coatedwith one of gold, silver, and conductive polymer, and thus conductivityof electrons and ions of the common collector layer 1300 is furtherimproved and interfacial resistance is further decreased.

Particularly, when the surface is coated with the conductive polymer,because the conductive polymer simultaneously serves as a conductor anda bonding material, the interfacial adhesion is further increased. Theconductive polymer may be any polymer having conductivity, but it ispreferable to use any one selected from the group consisting ofpolypyrrole, polyaniline, polythiophene, and polyacetylene in view ofimproving conductivity and interfacial adhesion of the collector.

According to the fourth embodiment of the present invention, since theplurality of silicon secondary battery unit cells forming the siliconsecondary battery unit has a structure in which the plurality of siliconsecondary battery unit cells are connected in series and stacked, highvoltage and high output power characteristics can be achieved whencompared to a conventional secondary battery unit having a structure inwhich the plurality of silicon secondary battery unit cells areconnected in parallel.

Further, since a common collector layer is used when the plurality ofsilicon secondary battery unit cells are connected in series andintegrated to form the silicon secondary battery unit, about half of thenumber of collectors included in each silicon secondary battery unit isreduced, and thus the weight of the collectors having a relatively largeportion in the total weight of the silicon secondary battery unit can beremarkably reduced, and a silicon secondary battery unit product that ismuch lighter than a conventional silicon secondary battery unit productcan be manufactured.

A battery module which supplies power to an electric vehicle as anapplication example of the silicon secondary battery unit according tothe fourth embodiment of the present invention will be described in moredetail with reference to FIG. 6 below.

The battery module for an electric vehicle according to the presentinvention includes a case 2100 for accommodating a silicon secondarybattery therein, a cover 2200 which covers an opening of the case and isprovided with output terminals 2500 which outputs power, and a pluralityof silicon secondary battery units 2000 according to the fourthembodiment which are disposed in the case 2100, and the siliconsecondary battery units 2000 are disposed to be connected in series.

The case 2100 may have any structure in which a silicon secondarybattery may be accommodated, but it is preferable to have a framestructure, through which external air smoothly passes, in order toovercome degradation of charge and discharge characteristics and shortlifetime of battery product caused by an increase in temperature of abattery module and heat accumulated in the battery module. The structureof the case 2100 shown in FIG. 6 is only an example of a framestructure, and various types of frame structures in addition to theexample may be employed.

It is preferable that the cover 2200 include a positive electrode busbar2300 connected to positive electrode terminals 2010 of the siliconsecondary battery units 2000 and electrically connected the outputterminal 2500 and a negative electrode busbar 2400 connected to negativeelectrode terminals 2020 of the silicon secondary battery units 2000 andelectrically connected to the output terminal 2500 in consideration ofstructural efficiency of the battery module.

Materials of the case 2100 and the cover 2200 are not particularlylimited, but the materials may preferably be an insulating material toprevent generation of an electrical short circuit caused when outputpower is distributed to somewhere other than an output terminal, andparticularly, it is most preferable to use plastic as the insulatingmaterial to secure sufficient durability and light weight of the caseand the cover.

When the battery module of the present invention is applied to anelectric vehicle, since the silicon secondary battery units includingthe common collector layer are used, the weight thereof is smaller thanthat of a conventional battery module, and thus a mileage of theelectric vehicle can be improved.

Particularly, since the plurality of silicon secondary battery unitsincluded in the battery module are formed to have a structure in which aplurality of silicon secondary battery unit cells are connected inseries, the battery module having high capacity and high output powercan be manufactured, and furthermore, when active material layers ofsilicon secondary battery unit cells included in the silicon secondarybattery unit are stacked as the structure described above, a batterymodule product can be manufactured to have higher capacity and outputpower than a conventional battery module for an electric vehicle in thesame volume.

<Fifth Embodiment>

Hereinafter, a silicon secondary battery according to a fifth embodimentof the present invention will be described in detail.

The fifth embodiment of the present invention relates to a siliconsecondary battery which is charged and discharged using silicon ions,and more particularly, to a silicon secondary battery including a firstsilicon multilayer thin film part in which a plurality of siliconpositive electrode thin film layers each formed of a first siliconcompound, which generates silicon cations when the silicon secondarybattery is charged and generates silicon anions when the siliconsecondary battery is discharged, are stacked, a second siliconmultilayer thin film part in which a plurality of silicon negativeelectrode thin film layers each formed of a second silicon compound,which generates silicon anions when the silicon secondary battery ischarged and generates silicon cations when the silicon secondary batteryis discharged, are stacked, and a collector configured to collectcharges, and the collector has a porous net shape.

In the fifth embodiment of the present invention, the collector isbonded to one end of each of the first silicon multilayer thin film partand the second silicon multilayer thin film part to collect charges, andstainless steel, nickel, and so on may be used for a material thereof.

A shape of the collector is not particularly limited, but it ispreferable to have a porous net shape or foamed shape to reduceinterfacial resistance by increasing an interface contact area betweenthe collector and the first and second silicon multilayer thin filmparts and to improve interfacial adhesion in a pressing process. Theporous net shape may be a two-dimensional planar porous net shape orthree-dimensional porous net shape.

Further, when the collector has a porous net shape or foamed shape, asurface of the collector is coated with one of gold, silver, andconductive polymer, and thus conductivity of electrons and ions of thecollector is further improved and interfacial resistance is furtherdecreased.

Particularly, when the collector is coated with the conductive polymer,because the conductive polymer simultaneously serves as a conductor anda bonding material, the interfacial adhesion is further increased. Theconductive polymer may be any polymer having conductivity, but it ispreferable to use any one selected from the group consisting ofpolypyrrole, polyaniline, polythiophene, and polyacetylene in view ofimproving conductivity and interfacial adhesion of the collector.

<Sixth Embodiment>

Hereinafter, a silicon secondary battery according to a sixth embodimentof the present invention will be described in detail.

The sixth embodiment of the present invention relates to a micro-batteryincluding a silicon secondary battery, and the micro-battery includes asilicon secondary battery including a first silicon multilayer thin filmpart in which a plurality of silicon positive electrode thin film layerseach formed of a first silicon compound, which generates silicon cationswhen the silicon secondary battery is charged and generates siliconanions when the silicon secondary battery is discharged, are stacked, asecond silicon multilayer thin film part in which a plurality of siliconnegative electrode thin film layers each formed of a second siliconcompound, which generates silicon anions when the silicon secondarybattery is charged and generates silicon cations when the siliconsecondary battery is discharged, are stacked, and a solid electrolytelayer located between the first silicon multilayer thin film part andthe second silicon multilayer thin film part and configured to deliversilicon ions between the first silicon multilayer thin film part and thesecond silicon multilayer thin film part when the silicon secondarybattery is charged and discharged.

Further, in the sixth embodiment of the present invention, it ispreferable that a positive electrode collector configured to collectcharges be bonded to one side surface of the first silicon multilayerthin film part, a negative electrode collector configured to collectcharges be bonded to one side surface of the second silicon multilayerthin film part, one side end of the positive electrode collector beattached to a substrate, and at least a part of the negative electrodecollector other than a surface thereof in contact with the secondsilicon multilayer thin film part be attached to the substrate forelectrically connecting the collectors to the substrate for charging anddischarging the silicon secondary battery.

Further, the micro-battery according to the sixth embodiment of thepresent invention preferably has a structure in which at least thesecond silicon multilayer thin film part, the solid electrolyte layer,and the negative electrode collector are insulated from the positiveelectrode collector to prevent a short circuit between electrodes, andto this end, it is preferable that a space be formed between sidesurfaces of the second silicon multilayer thin film part, the solidelectrolyte layer, and the negative electrode collector and the positiveelectrode collector.

The space may be an empty space, but it is preferable that the space befilled with an insulating material to further increase insulation and tofurther improve durability of the micro-battery.

In the sixth embodiment of the present invention, the first siliconcompound and/or the second silicon compound may include elastic carbonto prevent the degradation of the charge and discharge characteristicsof an active material layer because the volume of the active materiallayer is increased as the silicon secondary battery is repeatedlycharged and discharged. Since the first silicon compound and/or thesecond silicon compound include elastic carbon, even when siliconparticles are enlarged due to repeated charge and discharge, a volumeoffset effect may be shown by the elastic carbon, thereby suppressingthe bulking of the entire active material layer.

However, when the first silicon compound and/or the second siliconcompound include elastic carbon, since ion mobility or electronconductivity may be slightly lowered due to a gap between siliconparticles and elastic carbon, in order to compensate for this, it may bepreferable to further include conductive carbon or to use fullerenesimultaneously having elasticity and high ion mobility or electronconductivity as the elastic carbon.

Further, in the sixth embodiment of the present invention, the firstsilicon compound and/or the second silicon compound may include inactivematerial particles, which do not participate in a bulking reaction ofthe active material layer, to prevent the degradation of the charge anddischarge characteristics caused when the volume of the active materiallayer is increased as the silicon secondary battery is repeatedlycharged and discharged. The inactive material particles are one or moremetal particles selected from the group consisting of Mo, Cu, Fe, Co,Ca, Cr, Mg, Mn, Nb, Ni, Ta, Ti, and V.

However, when the first silicon compound and/or the second siliconcompound include the inactive material particles as described above,since the electric capacity of the silicon secondary battery may beslightly reduced, it may be preferable to further include conductivecarbon or conductive polymer.

In the sixth embodiment of the present invention, the positive electrodethin film layer and/or the negative electrode thin film layer may haveany shape which may form a layer, but it may be preferable to have amesh shape to minimize the risk of breakage of the thin film layer dueto contraction and expansion of the positive electrode thin film layerand/or the negative electrode thin film layer caused by repeatedlycharging and discharging the silicon secondary battery.

In the sixth embodiment of the present invention, the positive electrodethin film layer and/or the negative electrode thin film layer are notparticularly limited in surface shape, but it is preferable that aninterface contact area with an adjacent layer be widen andconcavo-convex shapes be formed on one or both surfaces of the thin filmlayer to reduce interfacial resistance.

In the sixth embodiment of the present invention, the first siliconmultilayer thin film part and/or the second silicon multilayer thin filmpart may be preferable to include an interlayer formed of a metal orcarbon allotrope to improve charge and discharge characteristics and tosecure uniform ion conductivity.

A thickness of the interlayer is not particularly limited, but it may bepreferable that the thickness be smaller than those of the first siliconmultilayer thin film part and the second silicon multilayer thin filmpart in view of increasing an electric capacity thereof.

A metal included in the interlayer may be any metal having high electricconductivity, but it may be preferable to use one selected amongaluminum, gold, and silver or an alloy containing two or more ofaluminum, gold, and silver in view of maximizing the performance ofcharge and discharge of a battery.

Further, a type of carbon allotrope included in the interlayer is notparticularly limited, but it may be preferable to use one selected amonggraphene, a carbon nanotube, and fullerene in view of securing uniformion conductivity in an electrode.

An example shown in FIG. 7 will be described below to facilitateunderstanding of the micro-battery according to the sixth embodiment ofthe present invention.

Referring to FIG. 7, in the micro-battery of the present invention, afirst silicon multilayer thin film part 3200 corresponding to a positiveelectrode active material layer and having a stacked structure, a solidelectrolyte layer 3100, and a second silicon multilayer thin film part3300 corresponding to a negative electrode active material layer andhaving a stacked structure are sequentially pressurized and stacked, apositive electrode collector 3400 is bonded to an upper surface of thefirst silicon multilayer thin film part 3200, and a negative electrodecollector 3500 is bonded to a lower surface of the second siliconmultilayer thin film part 3300.

Particularly, referring to FIG. 7, one side end of the positiveelectrode collector 3400 is bonded to a surface of a substrate 3000, asurface of the negative electrode collector 3500 opposite a surface ofthe negative electrode collector 3500 in contact with the second siliconmultilayer thin film part 3300 is bonded to the substrate 3000, and thusthe micro-battery of the present invention is electrically connected tothe substrate and may be charged and discharged.

Further, referring to FIG. 7, a space 3700 is formed between right sidesurfaces of the first silicon multilayer thin film part 3200, the solidelectrolyte layer 3100, the second silicon multilayer thin film part3300, and the negative electrode collector 3500 and the positiveelectrode collector 3400, and the space 3700 is filled with aninsulating material in FIG. 7.

Among the electronic components included in a printed circuit board(PCB), there are components which consume a constant current andcontinuously maintain constant functions such as an operation of atimer. In order to maintain operations of the components includedtherein, a button-type battery is inserted into the PCB or alithium-based battery is mounted therein to ensure operations of thecomponents.

A button-type battery is a primary battery and has an advantage of longoperating time, but has a burden of leakage and replacement after thebattery is discharged, and a lithium-based battery is disadvantageous inthat the lithium-based battery is bulky and has instability with respectto shock heat.

However, since the micro-battery according to the sixth embodiment ofthe present invention may be manufactured in a thin film type and may bealso manufactured in a chip type, the micro-battery can be made to havea large-capacity power supply structure using a cross section or a spacehaving no component of a PCB and can be a secondary battery capable ofbeing charged and discharged which is chargeable when the PCB operates.

Further, a shape of the micro-battery according to the sixth embodimentof the present invention is not limited when bonded to a planer surface,and can be mounted on a PCB by being manufactured to have a thickness of2 mm when manufactured in a chip type.

Therefore, another aspect of the present invention is related to a PCBsubstrate having a portion on which the micro-battery according to thesixth embodiment is mounted as a backup power source.

Further, since the micro-battery according to the present invention maybe manufactured to be integrated with upper and lower ends of a chip bya deposition process in a manufacturing process of a semiconductor chip,the micro-battery can be manufactured in a small size as an auxiliarycomponent mounted on the outside and can maintain power for a short timeas a backup power source against instant discharging.

Therefore, still another aspect of the present invention is related toan integrated semiconductor chip having a portion on which themicro-battery according to the sixth embodiment is deposited as a backuppower source.

In addition, the micro-battery according to the sixth embodiment of thepresent invention is provided as a component and can be utilized for awide-band semiconductor, a super capacitor, etc.

<Seventh Embodiment>

Hereinafter, a silicon secondary battery according to a seventhembodiment of the present invention will be described in detail.

The silicon secondary battery according to the sixth embodiment of thepresent invention has a basic structure in which a positive electrode isformed of silicon carbide of which a chemical formula is SiC, a negativeelectrode is formed of silicon nitride of which a chemical formula isSi₃N₄, and a nonaqueous electrolyte, which is made by any one type of anion exchange resin among polymers having a cationic sulfonic acid group(—SO₃H), a carboxyl group (—COOH), an anionic quaternary ammonium group(—N(CH₃)²C₂H₄OH), or a substituted amino group (—NH(CH₃)²) as a binder,is employed between the positive electrode and the negative electrode,and is a solid secondary battery of which the positive electrodegenerates cations of silicon (Si⁺) and the negative electrode generatesanions of silicon (Si⁻) when the silicon secondary battery is charged.

Further, in another structure of the silicon secondary battery, thepositive electrode may be formed of silicon carbide of which a chemicalformula is SiC, and the negative electrode may be formed of siliconnitride of which a chemical formula is Si₃N₄.

Such a silicon secondary battery includes a nonaqueous electrolyte madeby any one type of ion exchange inorganic material among tin chloride(SnCl₃), a solid solution of magnesium zirconium oxide (ZrMgO₃), a solidsolution of calcium zirconium oxide (ZrCaO₃), zirconium oxide (ZrO₂),silicon-βalumina (Al₂O₃), nitrogen monoxide silicon carbide (SiCON), andsilicon zirconium phosphate (Si₂Zr₂PO) and employed between the positiveelectrode and the negative electrode, and is a secondary batteryincluding a solid electrolyte part of which the positive electrodegenerates cations of silicon (Si⁺) and the negative electrode generatesanions of silicon (Si⁻) when the silicon secondary battery is charged,and the electrolyte part may be made in a liquid type.

A method of manufacturing the silicon secondary battery includes forminga positive electrode collector layer by metal-sputtering on a base,forming a positive electrode layer by vapor deposition with siliconcarbide (SiC) on the positive electrode collector layer, forming anonaqueous electrolyte layer by coating on the positive electrode layer,forming a negative electrode layer by vapor deposition with siliconnitride (Si₃N₄) on the nonaqueous electrolyte layer, and forming anegative electrode collector layer by metal-sputtering.

In a basic principle of the silicon secondary battery, the positiveelectrode includes an SiC compound which is in the most stable state ofsilicon carbide and the negative electrode includes an Si₃N₄ compoundwhich is in the most stable state of silicon nitride.

When the silicon secondary battery is charged by the positive electrode,silicon is easier to be changed to oxidation number than carbon, and inaddition to this, because the most stable state of silicon is atetravalent state and the second stable state thereof is a binary state,the following chemical reaction is performed.2SiC→SiC₂+Si⁺ +e ⁻

Conversely, when the silicon secondary battery is discharged, thefollowing chemical reaction is performed.SiC₂+Si⁺ +e ⁻→2SiC

In Si₃N₄, which is the most stable state of silicon nitride, of thenegative electrode, a state of silicon is changed from a tetravalentstate to a trivalent state, a state of nitrogen is changed from atrivalent state to a binary state, the compound is then changed to anSi₂N₃ compound which is in the second stable state, and thus thefollowing chemical formula is made.3Si₃N₄ +e ⁻→4Si₂N₃+Si⁻

Conversely, when the silicon secondary battery is discharged, thefollowing chemical reaction is performed.4Si₂N₃+Si⁻→3Si₃N₄ +e ⁻

The silicon secondary battery may express charging and discharging tothe following chemical reaction, but an additional material may beincluded therein so that charging and discharging efficiency can beimproved.

Generally, both of the SiC compound and the Si₃N₄ compound have acrystalline structure, and for example, when the positive electrode andthe negative electrode are formed by a general method such as a plasmadischarging method or the like, silicon carbide made by the SiC compoundhaving a crystalline structure and silicon nitride made by the Si₃N₄compound having a crystalline structure are formed.

However, to easily and smoothly charge and discharge the siliconsecondary battery which generates silicon ions (Si⁺ and Si⁻), eachcompound preferably is in an amorphous state instead of having acrystalline structure, that is, an amorphous structure.

To this end, as described below, a method of stacking both of thepositive electrode and the negative electrode by vapor deposition issuitably employed.

In addition, a space between the positive electrode and the negativeelectrode is divided into two spaces, both of cationic and anionicelectrolytes may be employed so that one side (e.g., an upper side) isfilled with the cationic electrolyte and the other side (e.g., a lowerside) is filled with the anionic electrolyte.

A nonaqueous electrolyte in a fixed state is used for the electrolyte ofthe silicon secondary battery, and the reason is that, in the case ofthe nonaqueous electrolyte in the fixed state, the positive electrodeand the negative electrode can be bonded in a stable state and efficientconductivity can also be achieved by enabling the positive electrode tobe near the negative electrode due to a form of a thin film.

The nonaqueous electrolyte may include either an ion exchange resin of apolymer or an ion exchange inorganic compound of a metal oxide.

The ion exchange resin may include any polymer having any one type of acationic sulfonic acid group (—SO₃H), a carboxyl group (—COOH), ananionic quaternary ammonium group (—N(CH₃)²C₂H₄OH), a substituted aminogroup (—NH(CH₃)²), and so on as a binder.

However, polyacrylamide methyl propanesulfonic acid (PAMPS) having asulfonic acid group (—SO₃H) can be suitably employed in that electrons(e⁻) moves smoothly without any difficulty.

However, when the ion exchange resin of a polymer is employed and onlythe ion exchange resin simply fills between the positive electrode andthe negative electrode, a case in which a suitable gap for smoothlymoving electrons (e⁻) may not be formed can occur.

To cope with the above situation, it is preferable to employ anembodiment in which a polymer alloy having a crystalline structureformed by a blend with the ion exchange resin and another crystallinepolymer is employed as a nonaqueous electrolyte.

Further, to implement the blend with the ion exchange resin and anothercrystalline polymer, since the ion exchange resin has polarity, it isnecessary to cope with the depolarization of the polarity of the ionexchange resin by the crystalline polymer.

In the case of the above blend, availability of the blend can bepredicted with a high probability on the basis of a difference betweensolubility parameters (SP values) of the ion exchange resin and thecrystalline polymer, and furthermore, on the basis of a value of anχ-parameter based on a combination of the solubility parameters.

It is preferable that the crystalline polymer of the plate include anion exchange resin such as atactic polystyrene (AA), a copolymer ofacrylonitrile-styrene (AS), or a copolymer of AA, acrylonitrile, andstyrene (AA-AS) for easy blending and maintaining crystallinity.

To maintain a crystalline structure of a mutually blended polymer alloy,it is necessary to consider a ratio of an amount of the ion exchangeresin to an amount of another crystalline polymer, and a specific valuethereof depends on the type of the ion exchange resin and anothercrystalline polymer.

However, when the polarity of the ion exchange resin is strong, a weightratio of another crystalline polymer may be made more than ½ of thetotal weight.

When a cationic ion exchange resin is provided as described above andanother crystalline polymer with respect to a cationic PAMPS employs AA,a copolymer of AS, or a copolymer of AA-AS, a weight ratio of the formerto the latter is suitably in the range of 2:3 to 1:2.

The nonaqueous electrolyte is not limited to the above described ionexchange resin and may also employ an ion exchange inorganic material,and tin chloride (SnCl₃), a solid solution of magnesium zirconium oxide(ZrMgO₃), a solid solution of calcium zirconium oxide (ZrCaO₃),zirconium oxide (ZrO₂), silicon-βalumina (Al₂O₃), nitrogen monoxidesilicon carbide (SiCON), phosphoric acid zirconium silicon (Si₂Zr₂PO),and so on may be employed as typical examples.

In the solid secondary battery, shapes of the positive electrode and thenegative electrode and an arrangement state are not particularlylimited.

However, an arrangement state of stacked materials in a plate shape andan arrangement state of stacked materials in a cylindrical shape may beemployed.

In an actual solid secondary battery, bases are formed on both of apositive electrode and a negative electrode, and the positive electrodeand negative electrode are connected to each other with a positiveelectrode collector layer and a negative electrode collector layerinterposed therebetween.

A discharging voltage between a positive electrode and a negativeelectrode depends on a degree of a charging voltage and internalresistance of the electrodes, but, as described below, an embodiment ofa secondary battery which maintains a discharging voltage of 4 to 3.5 Vcan be sufficiently designed in the case of a charging voltage of 4 to5.5 V.

An amount of a current flowing between electrodes may be fixed inadvance when the secondary battery is charged, but, as described below,an embodiment which changes a charging voltage to be in a range of 4 to5.5 V and also maintains a discharging voltage of 4 to 3.5 V can besufficiently designed by setting a current density per unit area of 1cm² to about 1.0 A.

As described above, the exemplary embodiments of the silicon secondarybattery and the method of manufacturing the same according to thepresent invention have been described.

The foregoing is illustrative of embodiments and is not to be construedas limiting thereof, and the scope of the present invention may beindicated by the appended claims rather than by the foregoing detaileddescription. It is intended that all changes and modifications that arewithin the meaning and the range of the claims and also come from theequivalent concept of the claims should be interpreted within the scopeof the present invention.

The invention claimed is:
 1. A micro-battery comprising a siliconsecondary battery, the silicon secondary battery comprising: a firstsilicon multilayer thin film part in which a plurality of siliconpositive electrode thin film layers each formed of a first siliconcompound, which generates silicon cations when the silicon secondarybattery is charged and generates silicon anions when the siliconsecondary battery is discharged, are stacked; a second siliconmultilayer thin film part in which a plurality of silicon negativeelectrode thin film layers each formed of a second silicon compound,which generates silicon anions when the silicon secondary battery ischarged and generates silicon cations when the silicon secondary batteryis discharged, are stacked; a solid electrolyte layer located betweenthe first silicon multilayer thin film part and the second siliconmultilayer thin film part and configured to deliver silicon ions betweenthe first silicon multilayer thin film part and the second siliconmultilayer thin film part when the silicon secondary battery is chargedand discharged; a positive electrode collector bonded to one sidesurface of the first silicon multilayer thin film part; and a negativeelectrode collector bonded to one side surface of the second siliconmultilayer thin film part, wherein a space is formed between thepositive electrode collector and at least side portions of the secondsilicon multilayer thin film part, the solid electrolyte layer, and thenegative electrode collector so that the second silicon multilayer thinfilm part, the solid electrolyte layer, and the negative electrodecollector are insulated from the positive electrode collector.
 2. Themicro-battery of claim 1, further comprising a substrate, wherein thepositive electrode collector has an extended portion extended from oneend of the positive electrode collector towards the substrate to be incontact with the substrate.
 3. The micro-battery of claim 1, furthercomprising a substrate, wherein, a surface of the negative electrodecollector opposite to a surface of the negative electrode collectorfacing the second silicon multilayer thin film part is bonded to thesubstrate.
 4. The micro-battery of claim 1, wherein the space is filledwith an insulating material.
 5. The micro-battery of claim 1, wherein atleast one of the first silicon compound and the second silicon compoundinclude elastic carbon.
 6. The micro-battery of claim 5, wherein atleast one of the first silicon compound and the second silicon compoundfurther include conductive carbon.
 7. The micro-battery of claim 5,wherein the elastic carbon includes fullerene or expanded graphite. 8.The micro-battery of claim 1, wherein at least one of the first siliconcompound and the second silicon compound include inactive materialparticles.
 9. The micro-battery of claim 8, wherein at least one of thefirst silicon compound and the second silicon compound further includeconductive carbon or a conductive polymer.
 10. The micro-battery ofclaim 1, wherein at least one of the positive electrode thin film layerand the negative electrode thin film layer are formed in a mesh shape.11. The micro-battery of claim 1, wherein at least one of the firstsilicon multilayer thin film part and the second silicon multilayer thinfilm part include an interlayer formed of a metal or carbon allotrope.12. The micro-battery of claim 11, wherein the interlayer is thinnerthan the first silicon multilayer thin film part and the second siliconmultilayer thin film part.
 13. The micro-battery of claim 11, whereinthe metal includes any one selected among aluminum, gold, and silver oran alloy containing two or more of aluminum, gold, and silver.
 14. Themicro-battery of claim 11, wherein the carbon allotrope includes any oneselected among graphene, a carbon nanotube, and fullerene.
 15. Themicro-battery of claim 1, wherein concave-convex shapes are formed onone surface or both surfaces of at least one of the positive electrodethin film layer and the negative electrode thin film layer.
 16. Themicro-battery of claim 1, further comprising a substrate on which thenegative electrode collector is formed, wherein the positive electrodecollector has an extended portion extended from one end of the positiveelectrode collector towards the substrate to be in contact with thesubstrate; and the space is formed between the extended portion of thepositive electrode collector and the side portions of the second siliconmultilayer thin film part, the solid electrolyte layer, and the negativeelectrode collector to insulate the second silicon multilayer thin filmpart, the solid electrolyte layer, and the negative electrode collectorfrom the positive electrode collector.
 17. The micro-battery of claim 1,further comprising a mesh plate in at least one of the first siliconmultilayer thin film part and the second silicon multilayer thin filmpart.
 18. A printed circuit board (PCB) substrate having a portion onwhich the micro-battery of claim 1 is mounted as a backup power source.19. A semiconductor chip having a portion integrated with themicro-battery of claim 1, which serves as a backup power source, using adeposition method.